Water flow detector and alarm means



Feb. 22, 1938. c. c. JOHNSON WATER FLOW DETECTOR AND ALARM MEANS Filed June 25, 1935 4 Sheets-Sheet 1 INVEN'FOR- 'iarence CJZznso z; M

ATTGRNEY- i Feb. 22; 1938.

c. c. JOHNSON V WATER FLOW DETECTOR AND ALARM MEANS 4 Sheets-Shegt 2 Filed June 23, 1933 MMM I ATTORNEY- Feb. 22, 1938. c c JOHNSON 2,109,317

WATER FLOW DETECTOR AND ALARM MEANS File d June 23, 1933 4 Sheets-Sheet 3 INVENTOR- Clarence CJbhnaon;

4 Sheets-Sheet 4 Feb. 22, 1938. c. c JOHNSON WATER FLOW DETECTOR AND ALARM MEANS Filed June 23, 1933 INVENTOR- Clarence Alb/222.5022;

av 6 ATTORNEY- Patented Feb. 22, 1938 UNITED STATES PATENT OFFICE WATER FLOW DETECTOR AND ALARM MEANS Application-lune 23, 1933, Serial No. 677,202

6 Claims.

This invention relates to water-flow detectors and alarms for water-flow-operated sprinklersystems, and more particularly to a water flow detector having operating means for an electric alarm system for causing an alarm when sprinkler heads discharge, and for preventing alarm from water-hammer in the sprinkler system.

Said detector comprises riser-pressure operated means communicating with an intermediate part of the riser oi' the sprinkler system and adapted to control an alarm operating means operated by the pressure-operated means when the pressure in the conduit decreases as when the sprinkler heads are discharging during fire, and held against operation when the pressure in the conduit increases, as by water hammer.

Said detector includes a surge passage communicating with the riser or other conduit and provided with an air chamber portion at its outer part, and a diaphragm disposed across the passage between the riser and said chamber portion and adapted to control an alarm operating lever connected to an active portion of the diaphragm,

and adapted to operate the alarm only when to remove the restricting means as for cleaning or adjustment; and objects of the present invention are to provide a flow detector of the kind means for retarding pressure flow toward the air chamber, and cut-oft valves for cutting off the restricting means from other parts of the apparatus before removing the restricting means.

Other objects are to provide signal controlling means for normally preventing tampering with the detector, and notifying as to whether the detector has been put in operative condition.

Another object of the invention is to provide an arrangement whereby a false alarm will not be sent, by the detector of a conduit from which there is no sprinkler discharge, when there is lowered pressure caused by discharge in a nearby communicating conduit.

Other objects of the invention are to improve generally the simplicity and eiliciency of such devices and to provide a simple device or apparatus of this kind which is economical, durable, sensitive and very reliable in operation, and eo0- nomical to manufacture and install,

noted having an improved removable restricting Still other objects of the invention will appear as the description proceeds; and while herein details of the invention are described in the specification and some of the claims, the invention is not limited to these, since many and various changes may be made without departing from the scope oi the invention as claimed in the broader claims.

Theinventive features for accomplishing these and other objects are shown herein in connection with an improved flow detector which, briefly stated, includes a diaphragm chamber, an air chamber and a conduit connecting said chambers with a riser. One of said conduits has therein a constricting means removable through a plugged opening to the exterior of the conduit. Cut-off valves in the conduit respectively at both sides of the constricting means allow the constricting means to be removed without draining the chambers, and allow the air chamber to be drained L without draining the inner portion of the diaphragm chamber.

Means secured to said diaphragm operate an exterior switch which may control a signal system; A removable tamper-preventing housing received over said valves and switch has therein a signal controlling tamper-switch held inaccessible in non-alarm condition by said housing when the housing is closed in place.

Said valves are so positioned and held as to prevent said housing from being positioned in place when one oi the valves or said restricting means is not left in position tor normal operation of the flow detector,

In the accompanying drawings showing, by way of example, two of many possible embodiments of the invention,

Fig. 1 is a side elevation showing a water flow detector attached to a riser of a sprinkler system;

Fig. 2 is a iragmental end elevation, partly in section on the line 2--2 of Fig. 1;

Fig. 3 is a fragmental plan, partly in horizontal axial section;

Fig. 4 shows a section through the diaphragm;

Fig. 5 is a diagrammatic iragmental vertical sectional view, showing the principal features of the device;

Figs. 6 and 7 are side and end elevations, showing the housing;

Fig. 8 is a section taken on the line 8-8 of Fig. 2 looking in the direction of the arrows of said line;

Fig. 9 is a fragmental sectional view taken on the line 9-'9 of Fig. 8;

Fig. 10 is a diagram showing detectors and alarm relay circuit;

Figs. 11 to 14 are diagrammatic views similar to Fig. 5, and show alternative forms the invention;

Fig. 15 shows a section taken on the line l5-i5 oi Fig. 14; and

Fig. 16 is a side elevation of the valve of Figs. 14 and 15. 10 My invention is shown in Figs. 1 and 5 incombination with a conduit or riser Ill for a sprinkler system i not shown) having branch pipes supplied by the riser and having sprinkler heads. A single surge conduit l4 communicates with the riser above the city check valve i5.

A few elements of the flow-detector will first be pointed out, after which the features of the invention will be described in detail.

Briefly indicated, the detector includes a diaphragm chamber 22, 23 (Fig. 8) having a diaphragm 26 thereacross dividing the chamber into inner and outer chamber portions, the inner portion 22 being connected by the surge conduit II with the riser It). the outer chamber portion 23 25 being connected by an outer passage 95, 34, 39

with an air chamber 40 (Fig. 5)

A by-pass conduit 43, H, l9, It connects said surge conduit and outer passage and has therein a constricting means 52, 59, B5, removable 30 through a plugged opening to the exterior of the by-pass. Cut-oil valves 51, 58 in the by-pass conduit respectively at both sides of the constricting valve allow the constricting means to be removed without draining the chambers, and allow the air chamber to be drained without draining the inner chamber portion.

Means 80, 93, 94 operated by said diaphragm operate switches iilil, ifll which may control a signal system. A removable tamper-preventing housing I94. I05 received over said valves and switch has therein a tamper-switch H9 (Fig. 2)

and adapted when open to send an alarm and to be held inaccessible in closed non-alarm condition by said housing when the housing is closed in place. Said valves and constricting means are so positioned and held as to prevent said housing from, being positioned in place when the handle 19 in one. or both of the cut-oil. valves is left in projecting cut-oi! position or when said 50 constricting means is left out oi its restricting position.

Now the flow detector will be described in detail.

My improved water flow detector comprises, an 55 inner member l8 (Fig. 1) and an outer member IS. The inner member comprises a vertical diskshaped chamber-wall portion 20 concaved at its inner face 2| (Fig. 8) to form the inner portion 22 of a diaphragm chamber 22. 22, said inner 60 portion communicating with the single surge conduit ll coaxial with said chamber portion and communicating with the riser above or below the valve, preferably above. Said outer member I! is provided at its inner end with a concaved disk 1:7, shaped flange portion 25 adJacent said first named disk-shaped portion 2|) to form the disk shaped diaphragm chamber 22, 23.

A diaphragm 26 (Fig. 8) across the diaphragm chamber divides the chamber into opposed pres- 70 sure compartments 22, 29 for water pressing on the diaphragm. Said diaphragm is shown as stamped to provide annular ribs and intervening grooves 29, 29, to give the diaphragm a sinuous cross section to permit bending of the ribs to 75 allow elongation of the diameter, and easy flexing of the diaphragm to increase sensitivity, the chamber walls being provided with corresponding annular grooves 39 in which the ribs of the diaphragm may nest, to prevent injury to the diaphragm under pressure. Clamping means such as stud bolts 33 passing through the edges of one of the diaphragm wall portions into the other serve for clamping the edge of the diaphragm therebetween.

Said outer member i9 is provided with an outer passage 34 (Fig. 8) and an intermediate chamber 95 alined and coaxial with the diaphragm chamber, a bushing ring 39 in the end of the intermediate chamber adjacent to the diaphragm chamber forming an inner passage 31. The outer end of the outer member is provided with a lateral flange portion 38 (Fig. 3) to which may be secured an upright conduit 39 (Fig. 5) having an air chamber 49 at its upper end, and a laterally curved lower portion provided with a flange 4i secured to said flange portion 38.

Said outer and inner members i9, H are provided with outer and inner upright pressure conduits I3, 44 (Figs. 1 and 8) communicating with said surge conduit l4 and outer passage 84 respectively, and a connecting passage 45 cooperating with telescoped pipes I9, 41 soldered together as at 49 to connect the conduits I3, 54 to communicate pressure in the riser and surge conduit to both of said diaphragm pressure compartments and the air chamber.

The lower part of said outer pressure conduit 44 is enlargedat its lower end to form a valve chamber 50 communicating with said connecting passage, and forming an upper valve seat 5|, and a lower threaded end 52 receiving a threaded plug 53 having an integral nut 59. The nut 55 is grooved and has a rotatable ring 54, secured by a chain 55 to the body l9, so that the plug 58 is held to body when removed. The plug 52 is provided with an upper projection 61 in the valve chamber provided with a vertical guide bore 59 slldably receiving the lower stem 59 of a constricting valve member having an upper tapered head 50 engaged with said seat 5|.

A spring 52 compressed between said head and plug presses said head on the seat and holds the valve to said seat under all conditions. Said valve member is formed with an axial bore 95 and lateral bores 84 communicating therewith. A die 85 in the enlarged upper part of the axial bore is provided with a small axial aperture 99 cooperating with the bores 99 and BI to provide an intermediate constricted passage allowing water and pressure to pass slowly to or from the air chamber until equilibrium is reached.

The outer member I! is provided with cut oi! valves 91 and 89 (Figs. 5 and 9) on both sides respectively of the constricting member 59, 99 said valves being disposed in bores transverse to the pressure conduit 40 and connecting conduit 45. Each of said bores is formed with a reduced tapered inner end 99 intersecting the conduit, and with a threaded outer end 10 (Fig. 9) receiving a screw plug ll having an axial bore receiving a stem 12 of a valve member II and having a transverse bore II in said tapered end 13. A compressible cup packing I! on said stem is compressed between said plug and head, yieldably holds the head in its seat, and prevents leakage past stem 12. A manipulating arm 19 carried on the outer end of the stem is limited in its angular movement by stop pins 11, 18 (Fig. l) and is dis- Posed in non-projecting position against the pin 19 when the valve does not close the conduit, and

is disposed, when the valve closes the conduit against the pin 11 in laterally projecting position for a reason to be explained hereinafter.

A plunger rod 88 (Fig. 8) secured axially to said diaphragm is guided axially of said passage 34 in a guide disk 8i in said passage having a central guide opening receiving the rod, and having intra-marginal perforations 82 to allow passage of liquid in the passage. Said outer body I8 has a large lateral opening 84 (Fig. 9) communicating with said chamber 85. A supporting plate 85 secured by screws 88 on the side of said outer member has a large opening registering with said lateral opening, and receives thereon a thick cup-shaped rubber fulcrum member 81 having an outer flange 88 flat on the outer face of said plate, and provided with an inner neck 88 having narrow opening therein. A clamping plate-member 88 is clamped, by screws 88, on the outer face of said flange 88 and has an inwardly pointing central tubular part 8I received in the cup member 81 secured thereon by wire bound around the cup. A lever 83, 94 mounted in a liquid-tight manner in said neck 88 is thereby intermediately fulcrumed, and has an electrically insulated outer contact end 83, an inner motive end 94 received in an opening 85 of the plunger rod 88. The neck 89 is bound by wire 86 into fluid-tight contact with the lever.

An adjustable plate 98 (Fig. l) slidably mounted on said supporting plate 85 is adjusted by means of an adjusting screw 98 and carries a double pole spring switch I88, I8I, corresponding members I88 of each switch being extended and connected with, and insulated from, each other by a block I82, one of the members I88 being normally just out of contact with, and engageable by, said insulatedactive end 83.

A partly cylindrical housing I84, I85 (Figs. 1 and 2) has a large inner end I85 and a smaller outer end I81 respectively fitting on said flange portions 25, 38, said ends having inner ribs I88, H8 at the inner face of the flange portions to prevent end-wise displacement of the housing.

Said housing comprises a pair of longitudinally carried on said supporting plate 85 and adapted to be engaged and held closed by said projections ill when the half sections are clamped closed and to be allowed by the projections to open before the lapped portions II2 of the joint are entirely unlapped thereby to prevent access to the switch until it is open.

A supporting bracket I28 (Fig. 3) on the upper part of said wall flange 25 carries a cable I2I mounted therein and extending out through an opening at the lapped joint of the housing. A terminal plate I22 mounted on the upper part of the outer member I8 has terminal screws, wires from said cable and screws being for the purpose of connecting said detector switch I88, I M in a suitable flow detector alarm circuit, and said supervising switch I I8 in a closed supervising circuit for indicating whenever the housing is removed. Said systems may be any suitable or well known system, the switches being normally open or closed as the system requires.

The operation will be easily understood by those skilled in this art. Water hammer causes a sudden surge of high pressure in the riser I8; and this sudden surge or other sudden high pressure in the riser cannot pass quickly through the constriction 55 (Fig. 8) to the chambers 23, 48, but is immediately communicated through the surge conduit I4 to the chamber portion 22 and the diaphragm, causing the diaphragm to move the active lever 83 (Figs. 1 and 9) away from the switches I88, IM to leave the switches open and the alarm inoperative. On the other hand, discharge by the sprinkler heads, as during a fire causes a decrease in pressure in the riser, above the valve I5 (Fig. 5). This or any other sudden decrease in pressure in the riser causes the pressure in the chamber portion 22 to decrease immediately, while pressure from the air chamber 48 is still transmitted to the diaphragm, and this causes the lever-end 88 to engage the switches I88, I8 I thereby to close the switches to energize said alarm means thereby to operate the alarm.

The restricted by-pass 65 permits slow equalization of pressure on both sides of the diaphragm, but will not during sprinkler discharge permit equalization, until after the lever 83, 84 has had time to cause the alarm.

The threaded outer end 53' (Fig. 8) of the plug 53 may be screwed into the part 52, whereupon the valves 81, 68 can be opened to rapidly fill the device. After filling the valves 81, 88 are closed, plug 53 assembled (as in Fig. 8), and the valves 81, 88 again opened, With the plug 53 removed from the threads 52, the covers I85 cannot be replaced.

The chamber portions 22, 28 may be kept normally entirely or partially filled with water or air, as found most desirable.

In devices of this kind, it is sometimes necessary to clean or adjust the constricting member 59, 88, 85 (Fig. 8); and this can be done by removing the plug 53 and associated parts in the enlargement 58.

When doing this it is usually desirable to cut off the water from the riser, which can be done by moving the handle I8 (Fig. 1) to the projecting position of the full lines. Also it is often desirable to remove the constricting member without draining the chambers 28, 35, 48; and this can be done by turning the handle I8 of valve 81 to projecting position.

These manipulations, of course, require that.

the housing I84, I85 be removed, thus opening the switch IIB, sending a signal that the housing is not in place. This housing cannot be replaced so as to close the switch 8 until the projecting handles I6 and the plug 52 have been restored to their proper places within the confines of the housing when entirely in closed, tamperswitch-closing, position.

The cup 8I and lever 83, 84 and associated parts may also be removed when the valve 68 is closed; but they must be replaced before the valve 88 is opened, else the housing would be flooded. Therefore, a signal that the switch H8 is closed, also indicates that the fulcrum cap and associated lever are in place.

When the system is operated without the city check valve I5 or when the check valve leaks or when there are a plurality of communicating branch conduits I8, I8" (Fig. 10) fed from a single supply conduit M, it may happen that near-by water discharge in a neighboring communicating conduit (as by a city fire hydrant or sprinklers of another branch conduit) may appreciably lower pressure at a pressure detec tor. To prevent this from sending a false alarm, the system shown diagrammatically in Fig. 10 is provided. This system takes advantage of the fact that such near-by water discharge causes a back how of water in the conduit I or I0" when the pressure is lowered.

In Fig. is shown a supply conduit M sup plying branch conduits I0. I0" communicating therewith, each branch conduit having a pressure controlled detector, as in Fig. 1, communicating therewith. The double detector switch 100, II as shown in Fig. 1 associated with each detector comprises a normally open shunt switch I00, IM and a normally open local switch I00, IIII' both adapted to be closed by the lever end 03 when pressure decreases in the branch conduit. A local alarm circuit I22 for each branch I0 or I0" is closed by said local switch I00, IOI' when operated, to notify the local attendant.

The supervisory alarm circuit ior each pressure detector includes a current source I25, a normally closed tamper switch iii, a slow release relay I28 and a resistance I21 connected in series by conductors I20, I20, I50, I3I and controls a supervisory alarm circuit switch I operated by said relay when released. It is understood that the showing of the relay I and other parts therein are merely illustrative and that other alarm means, circuits and parts may be used. Shunt conductors I24, I55 connect said shunt switches I00, IOI around said relay I and resistance I21, to short circuit and cut out the relay when the shunt switch I00, IOI closes when the associated sprinkler heads discharge. To prevent operation of the relay from lowered pressure in other conduits, I provide a flow detector I in each of said branch conduits, here but not necessarily shown between the pressure controlled detector and the supply conduit.

Normally closed flow detector switches I" interposed in said shunts I25 respectively are opened by said flow detectors when flow toward the supply main M takes place, to prevent the short circuiting of the relay I25 and operation of said supervisory alarm from back flow caused by water discharge or pressure reduction in other communicating conduits.

Should the cover I04, I05 be removed current in conductor I20 and associated relay I25 is interrupted, causing operation of the associated supervisory alarm.

Sometimes when there is a particularly violent water-hammer surge, the upward surge opens the valve I5 and causes a rise in pressure above the valve I I, which will cause an excessive rise in pressure above said valve much greater than normal.

This would cause a great diiference in pressure between the conduit I4 and the chambers and 25, which diflerence might interfere with the proper working of the apparatus before it could be equalized through the aperture 05. To prevent this interference there may be provided a by-pass I45, I40 (Fig. 11) around the apertured head 50.

..This by-pass I45, I40 communicates with the conduits 29' and is provided intermediateiy with a bail check valve I4'I opening toward the air chamber 40 and pressed on its seat by a spring I48 compressed between the ball and a screw plug I49 in a threaded opening through which the valve and spring may be inserted or removed. This spring I48 is strong enough to hold the ball valve in closed position except when sudden excess pressure in the upper part of the pipe I0, communicated through the duct I4 and by-pass section I45, lifts the ball valve from its seat and communicates equalizing pressure to the chamber 40.

On the other hand sudden lowered pressure in the upper part 01' the pipe l0 will merely cause the ball valve I" to remain pressed closed; and the diaphragm 25 will be operated as heretofore described.

Instead of the two valves 61, 50, I may provide valves 51', 61" in the upper ends of conduits 45' and I46 and a three way valve I50 at the riser end of section I45 (Fig. 11) may be used. In the position of the drawings, the system is in operative condition. When the valves GI'QGI" are open and valve I50 is turned to position to point the branch duct I5I directly downwardly, the duct 42' is closed so that plugs 53 and I49 may be removed and all parts of the apparatus except ducts i4 and 40' and inner chamber 22 maybe drained through the openings from which the plugs were removed. When the branch duct I5l is turned directly leftward. the ducts I4, 43' may be drained through outlet I52 without draining chambers 23 and 40. When the valves 61', 51" are closed and the branch duct I5I is downward the members 60 and lli may be removed without draining chambers 22, 25, 35 or 40.

Fig. 12 shows a somewhat simplified arrangement in which the apertured tapered head 60 is reversed to serve as a relief check valve in the place of the ball valve I" of Fig. 11. In Fig. 12, the seat 5i for the tapered head 60 is placed in the end of the conduit 45" which connects the conduit 42 with the conduit 44". The tapered head 50, plug 52 and connecting parts are the r same as in the previous figures except that the location and direction are changed and the spring 82' is made weak enough to release the head 60 from the valve seat when sudden pressure in the upper part of the pipe I0 is excessive, but strong enough to hold the head 00 on its seat during normal conditions and operation, so that the aperture 05 functions as in the previous figures.

A valve 51 may be interposed in the upper part oi the conduit 44"; and when this valve 61 is closed, and the branch conduit I5I of the member I50 (Fig. 12) is rightward, the parts 53 and 00 may be removed without draining chambers 22, 23, 35 and 40.

In Fig. 12 the three-way valve I50 is interposed intermediately of the conduit 45" and when the valve is as shown in Fig; 11, the apparatus is in condition for normal operation. If it be desired to drain the air chamber 40. the passage III is turned toward the head 60, thus closing access to the conduits 43 and I4 permitting drainage through the outlet I52. If it be desired to drain the parts to the left of the three way valve while maintaining the air chamber under pressure, the passage I5I is turned toward the passage 42, thus closing the chambers 23 and 40, but allowing conduits I4 and 43 to drain.

The valve I50 is shown controlled by a hand wheel I55 having a cut-out I It in the periphery which allows the cover I05 to be secured in place when the two-way valve is in normal position and the anchored plug 53 is in place. If the plug is out of place or ii the valve I50 is not in normal position, the cover I05 is thereby prevented from being secured in place. It is understood that Figs. 5, 11 and 12 are very diagrammatic for purposes of illustration.

In the form of invention shown in Fig. 13, the by-pass 44a, 65a shunts around said pressure operated diaphragm, and a flow-retarding apertured member 66 is interposed in said by-pass means as in Fig. 12; but an additional shunt conduit I45 serves as a by-pass around the apertured member and a removable check valve I41 in said shunt conduit I66 opens toward said chamber 66, and operates as described of the device of Fig. 11.

In Fig. 13 there is a hand shut off valve 66 in said by-pass 4641 between said shunt conduit 5a and the riser. end of said by-pass, and a hand valve 61 in said by-pass between said air chamber 46 and said shunt conduit Illa.

The manipulation for clearing the valves 66 and I 4'! of Fig. 13 is the same as in Fig. 5, except that closure of both valves 61 and 68 permits removal of both valves 60 and I41.

In the device of Figs. 14 to 16. the by-pass Mb, 45b around the pressure operated diaphragm is provided with an intermediate valve seat chamber I59 (Fig. 15), receiving a three way valve member I66 provided with an axial chamber I6! having a valve seat I62 at the inner end, and an inner port I63 normally connecting said inner end with the by-pass portion 45b, and an outer port I65 normally connecting the outer end part of the chamber IGI with the outer by-pass portion 44b. The removable plug 53 is the same as in Fig. 8 and is screwed in the outer end of said chamber I61, and a similar spring 62 compressed between said plug and the constricting valve member 60 holds the valve member on the seat I62 and allows it to yield toward said outer end of the chamber I6I, giving the member '60, the same function as described of Fig. 12.

Said valve seat chamber I69 has a lower drain duct I61 (Fig. 14) adapted at times to register with port I63 or I65 or a branch port I66 in said three way member communicating with said chamber I6I.

Said member I60 is adapted when in the position shown to leave the by-pass 46b, 45b unobstructed (except for the apertured member 60) for normal operation. when in position with the port I63 down, it connects both end parts 44b and 45b of the by-pass with said drain duct I61. When in position with ports inclined at 45 degrees both end parts of the by-pass are closed to allow removal of the plug 53 and check valve member without draining the apparatus. A handle I16 on the valve member may be positioned to prevent the securing of the cover in place except in normal position of the valve member.

If the port I63 is turned down, the whole apparatus may be drained. If the port I66 is turned down, the duct 43 may be drained without draining the chamber 60'. If the port I66 is turned down, the chamber 40 may be drained without draining the duct 43.

I claim as my invention:

1. In combination, an attachment for the fluid pressure line of a sprinkler system comprising a casing having an attaching portion, said casing having therein a surge passage which extends through said portion for communication with the interior of the line; means forming a by-pass around a part of the passage, said by-pass having therein a seat and there being a threaded opening associated with said seat; removable bypass constricting means having an apertured head engaged on said seat, a threaded plug engaged with the threads of said opening, and a compressed spring disposed between said plug and said head whereby to urge the latter against its seat.

2. In combination, a device adapted for attachment to the fluid pressure line of a sprinkler system comprising a casing having an attaching portion, said casing having therein a surge passage which extends through said portion for communication with the interior of the line; means forming a by-pass which has its opposite ends communicating with the passage, said bypass having therein a seat and there being a threaded opening leading to said seat, said opening having threads on its boundary face; removable by-pass constricting means having an apertured head engaged on said seat, a threaded plug engaged with the threads oi said opening, spring means disposed between said plug and said head and urging .the latter to its seat, and a pair of cut-oil valves for closing said by-pass, one valve being on each side of said constricting means.

3. A detector comprising a surge passage adapted to communicate with a riser and provided with a yielding pressure opposing means at its outer part; pressure operated means disposed across said passage and adapted to be pressed in opposite directions by pressure in said passage; means forming a by-pass conduit for said passage around said pressure operated means; a translating means controlled by the pressure operated means; said by-pass conduit being provided with a lateral opening and a closure therefor; and a removable member 'interposed' in said by-pass conduit and removable through said opening and provided with a constricting orifice.

4. A detector comprising a surge passage adapted to communicate with a riser and provided with a yielding pressure opposing means at its outer part; pressure operated means disposed across said passage and adapted to be pressed in opposite directions by pressure in said passage; means forming a by-pass conduit for said passage around said pressure operated means, said by-pass conduit having its end communicating with the passage; a translating means controlled by the pressure operated means; said bypass conduit having a lateral opening and a closure therefor; a removable member interposed in said by-pass conduit and provided with a con stricting orifice, said member being removable through said opening to allow cleaning of the oriflce; and cut-off valves in said by-pass conduit on each side of said member respectively closing the ends of the by-pass conduit during cleaning.

5. In a detector, in combination. a body passage adapted to communicate with a riser and provided with a yielding pressure opposing means, and pressure operated means adapted to be pressed in opposite directions by pressure in said passage; a translating means controlled by the pressure operated means; a portion of said passage being enlarged to form a valve seat; a constricting valve in said portion engaged with said seat and provided with a constricted passage therethrough; a removable plug in said enlarged portion; and a spring between the plug and valve to yieldably hold said valve in place.

6. A detector comprising a surge passage adapted to communicate with a riser and pro-. vided with a yielding pressure opposing means at its outer part; pressure operated means disposed across said passage and adapted to be pressed in opposite directions by pressure in said passage; a translating means controlled by the pressure operated means; structure means forming a. by-pass for said passage around said pressure operated means and an intermediate chamber portion in the by-pass; a chambered valve member interposed in said intermediate portion and provided with an axial chamber having a valve seat at the inner end, an inner port normally connecting said inner end with the riser 1 end oi the by-pass, and an outer port normally connecting the outer part of the chamber with the outer part of the by-pass; a removable apertured constricting check valve member engaged with said seat and yieldable toward the outer end of said chamber; said ports being positioned and adapted when in one position or the chambered member to leave the by-pass unobstructed for normal operation, and when in another position to close both end parts of the by-pass.

CLARENCE C. JOHNSON. 

